Prebiotics: Potential Benefits, Known Risks, and More

Note: The U.S. Food and Drug Administration (FDA) does not approve supplements for safety or effectiveness. Talk to a healthcare professional about whether a supplement is the right fit for your individual health, and about any potential drug interactions or safety concerns.

This guide will explain everything you need to know about prebiotics and how they impact your health.

Some potential health benefits of prebiotics include:

May Support Regular Bowel Movements

May Support a Healthy Immune System

May Lower Inflammation

May Improve Anxiety and Depression Symptoms

Still, more research is necessary, as most studies have been small, of short duration, and focused on women or people already taking medications, says Zachary Spiritos, MD, a neurogastroenterologist at UNC Health in Clayton, North Carolina, and founder of EverBetter Medicine, a telemedicine platform serving Illinois and North Carolina.

“We need larger and longer studies that include people from diverse backgrounds and track not just mood but also what is happening in the gut,” Dr. Spiritos says.

May Suppress Appetite

May Help Regulate Metabolism and Blood Sugar

Some “promising” research also suggests that prebiotics could help with managing or preventing type 2 diabetes via its influence on metabolic health, blood sugar, inflammation, and insulin sensitivity, says Raj Dasgupta, MD, associate program director of the internal medicine residency program at Huntington Memorial Hospital in Pasadena, California, and chief medical adviser for Garage Gym Reviews.

That said, most studies to date have been small, short-term, or done in very specific populations, Dr. Dasgupta notes. Larger, longer-term clinical trials on more diverse populations are needed, he says.

“The research is encouraging, but we need stronger evidence before prebiotics become a standard part of diabetes care,” Dasgupta explains. “For now, they could be a helpful addition to a healthy lifestyle, especially when paired with a balanced diet and other proven strategies."

May Decrease the Risk of Colon Cancer

“While animal and lab studies have shown potential mechanisms, large-scale, long-term studies in human populations are still needed to better understand how prebiotics could contribute to cancer prevention,” he explains.

There are a few potential mechanisms behind this, says Tracee Yablon Brenner, RD, a registered dietitian nutritionist at Holy Name Medical Center in Teaneck, New Jersey. These include:

• Increasing satiety: “When your gut bacteria ferment prebiotics, they produce SCFAs like butyrate and propionate,” Yablon Brenner says. “SCFAs may help signal to your brain that you’re full and reduce appetite.”

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• Nourishing beneficial bacteria: “Prebiotics help produce more helpful bacteria, such as bifidobacteria, which can influence metabolism and hunger hormones,” she explains.

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• Helping reduce inflammation: “Chronic, low-grade inflammation is linked to weight gain as well as insulin resistance,” she says. “A healthier gut (thanks to prebiotics) may help reduce inflammation — then it’s easier for your metabolism to function optimally.”

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• Improving blood sugar control: “Prebiotics can delay the absorption of sugar from your food, helping to reduce blood sugar spikes and crashes that lead to cravings,” she says.

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However, if you’re considering taking prebiotics as a supplement, be aware that the FDA regulates supplements differently than conventional drugs. Manufacturers can put a supplement on the market without FDA approval, and the FDA will only intervene if safety concerns arise. And the efficacy of supplements — whether they do what they claim — is not regulated at all.

Risks

Additionally, everyone should talk to their doctor before starting any new supplements, and when it comes to prebiotics, people with certain autoimmune conditions, those with liver or kidney disease, and women who are pregnant should be especially careful, because their bodies often respond differently, Yablon Brenner says.

Side Effects

Yablon Brenner says that the following may help minimize symptoms:

• If you’re sensitive, choose prebiotics that are gentle or low FODMAP (low in fermentable oligo-, di-, mono-saccharides and polyols), such as acacia or partially hydrolyzed guar gum. FODMAPs are not as well absorbed by the gut and may exacerbate symptoms in people with digestive issues like IBS or IBD.
• Take prebiotic supplements with food, and drink lots of water whether you’re eating prebiotic foods or taking a supplement.

In addition to occurring naturally in foods, prebiotics are available in a few different forms, Yablon Brenner says. Each has its advantages, but one isn’t necessarily more effective than another, she adds.

• Liquids
• Chewable tablets
• Gummies
• Powders
• Capsules

Powders and food-based forms usually offer better value and higher potency, Yablon Brenner says, adding that bulk powders such as acacia powder usually give the best bang for your buck. Gummies may be good for kids, while capsules might be preferable for adults and require no prep, she adds.

“Drinks and gummies are good for convenience but be mindful of added sugars or low fiber content,” Yablon Brenner notes. “It’s important to read labels carefully — some products market themselves as ‘prebiotic’ but contain very little actual fiber.”

Think about high-fiber foods, or “what grandma used to call roughage,” says Debbie Petitpain, RDN, a spokesperson for the Academy of Nutrition and Dietetics, based in Charleston, South Carolina. Fruits, vegetables, whole grains, and beans will provide the insoluble fiber that gut bacteria thrive on, she says.

Some foods are marketed as having prebiotics added to them, but since the FDA does not have an established definition for prebiotics, it can be difficult to know exactly what you’re buying, says Dasgupta.

Yablon Brenner says it’s generally better to get prebiotics through food, rather than from supplements, for a couple of reasons:

• Whole foods provide many additional nutrients. “Foods rich in prebiotics contain vitamins, minerals, fiber, and antioxidants,” she says, which support overall health and a healthy gut microbiome and may help protect against certain diseases.
• There’s a lower risk of side effects. “Prebiotic supplements can occasionally cause bloating or gas, especially in large doses,” she notes. But food sources are less likely to cause side effects, because they act gently and don’t deliver a large, single dose like supplements do, Yablon Brenner explains.

Prebiotic supplements are available over the counter in drugstores and supermarkets across the United States.

Here are some tips to select and preserve a quality supplement.

Selection

Remember that the FDA doesn’t regulate supplements the way it does conventional medicines, so you’ll want to be cautious. Here are a few things to consider:

• Look for branded ingredients. If a supplement has a branded ingredient, with a trademark or registered trademark symbol on the label, you can look at the product’s website to see what types of independent or third-party testing have been done to prove that ingredient’s efficacy.
• Check the label for certifications from USP, NSF, or ConsumerLab. This means the product has undergone third-party testing for quality and purity. “Third-party testing ensures that a particular supplement actually has what the company is advertising,” Pacheco says.
• Avoid prebiotic supplements with added colors, sweeteners, or fillers, Pacheco advises. “While the research is still emerging, there’s some preliminary evidence that these things may negatively impact gut health,” she says. “There are many options available that don’t contain them.”

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• Different types of prebiotic fibers may have distinct benefits and effects on your digestion, Pacheco says. “For example, inulin supports healthy gut bacteria, but it’s often sourced from chicory root extract, which can cause excessive gas, bloating, and diarrhea in some people,” she says.

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  “Acacia fiber supports the growth of beneficial bacteria such as bifidobacterium and lactobacilli — it’s usually gentle on digestion, so it may be a better option for someone who has digestive issues at baseline, such as someone with IBS.”

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• Many prebiotic supplements come with additional ingredients, such as probiotics. While both may be beneficial, Rao says you may want to speak to your doctor about trying one at a time to assess the effects of each one more accurately. “If you took a combined supplement, you would not know which ingredient is either causing side effects or working for you,” he says. However, this depends on your goals, Yablon Brenner notes. If your aim is to generally support or restore gut health, a combined probiotic-prebiotic supplement may be advantageous.
• One possible drawback of supplements is that they can be expensive. “If you’re specifically looking to rebalance the bacteria in your gut, you get more bang for your buck through whole foods,” Petitpain says. “Consumers should aim to consume the recommended number of fruits, veggies, and whole grains before adding supplements.”

Storage

Most prebiotic supplements — especially powders or capsules — do fine in a cool, dry cabinet, away from heat and sunlight, Dasgupta says.

“Some liquid forms, like syrups, might need to be refrigerated after opening,” he explains. “It really depends on the product, so it’s a good idea to check the label.”

Currently, there are no specific, official recommendations regarding the amount of prebiotics a person should consume each day, Rao says.

Many prebiotic supplements are labeled as having a very high dosage, but there’s no evidence that more is better, Rao adds. “There’s not enough evidence to indicate the correct dosage, as randomized control trials and safety trials still need to be done,” he says.

Dasgupta recommends starting at the lower end and working your way up — especially if you have a sensitive stomach — and speaking with your doctor before taking any supplements, especially at a high dose.

• Prebiotics are an important part of keeping your microbiome healthy and supporting your gut health. The best way to get them is to eat lots of high-fiber foods like asparagus, bananas, and beans, along with white vegetables like onions, garlic, and leeks.
  
• Research into prebiotics is ongoing, and there’s still a lot to learn about their potential benefits and drawbacks. Consult with your healthcare provider before taking a prebiotic supplement or increasing your fiber intake.
• Remember that supplements aren’t regulated by the FDA in the same way as conventional medications, so it’s important to look for features like third-party testing when selecting a product.